Field of the Invention and Related Art Statement
The present invention relates to an apparatus for recording an image having a size which is larger than a television image of one frame.
There have been proposed apparatuses for recording medical diagnostic images such as ultrasonic on a record medium such as a heat sensitive record paper or a photographic film. One known image recording apparatus is called a thermal line scan recorder, in which an image signal representing an ultrasonic or X-ray image is supplied to a thermal head. One image is recorded on a heat sensitive record paper which is fed through the thermal head at a constant speed, while the heat sensitive record paper is brought into contact with the thermal head. In such an image recording apparatus, the length of the thermal head is made equal to the length of a television image of one frame measured in one direction, e.g. in the longitudinal direction. The heat sensitive record paper has a width equal to the length of the thermal head, and the image signal is supplied to heating elements of the thermal head in such a manner that one scan line of the television image parallel to said direction is simultaneously recorded on the heat sensitive record paper. By moving the heat sensitive record paper over a distance which corresponds to the length of the television image measured in a direction perpendicular to said direction, e.g. in the lateral direction, it is possible to record a single complete image.
In the above mentioned known image recording apparatus, the width of the heat sensitive paper is made equal to the longitudinal length of the television image, and an image having the same size or area as the television image is recorded by moving the heat sensitive record paper over a distance equal to the lateral length of the television image. In such a known image recording apparatus, the size of the image recorded on the heat sensitive record paper is always constant. That is to say, in the known image recording apparatus, the recorded image has the same size as the television image of one frame. In this connection, it should be noted that the size of the television image does not mean the actual size of the television image displayed on a television monitor, because the actual size of the displayed television image is dependent upon the size of the screen of the television monitor. In accordance with progress in the application of ultrasonic and X-ray images to medical diagnosis, it has been required to record medical diagnostic images of various sizes. In order to meet such a request, in the known apparatus, a special interface board is arranged between the image recording apparatus and an image, generating apparatus for generating an ultrasonic or X-ray image, and the image signal generated by the image generating apparatus is recorded after being processed by the special interface board. It is apparent that such a special interface board could not be designed easily and the cost of the whole image recording system is liable to be expensive.